In the process of mounting a lighting fixture or electrical receptacle, for instance, it is usual and customary for interior construction to install electrical junction boxes against ceiling joists, wall studs or other upright structures used in framing buildings. Knock-out plugs are removed from the junction boxes which are then pre-wired with electrical conductors, telephone wires, television cable, and so forth. In subsequent steps of framing, wallboards or paneling having cut-outs for the junction boxes are applied to the walls and ceilings. In the final stages, lighting fixtures, switches, receptacles, etc., are wired to the junction boxes, secured with threaded fasteners, and outer plates affixed to the exterior to provide an attractive and finished appearance.
However, the installation of lighting fixtures, electrical switches, etc., to exterior walls present difficulties not normally experienced with the foregoing interior installations. Problems are especially prevalent when mounting electrical fixtures on the exterior sides of dwellings having irregular ceder shingles, lapped type siding with inclined surfaces, and so forth. Installation of electrical fixtures to exterior lapped walls would result not only in an unsightly appearance, but did not provide a secure weather-tight seal around the fixture. Frequently, efforts to solve these problems meant cutting out siding and mounting the fixture over the opening without the required support. This also provided an unfinished appearance because cutting often meant openings were irregular or oversized.
In an effort to solve the problems associated with exterior wall installations in which lapped type siding was employed various mounting systems were developed. Representative examples of outlet trim and wall mounting devices for electrical fixtures useful with lapped siding are disclosed by MacLeod et al in U.S. Pat. No. 4,920,708 and by Wimberly in U.S. Pat. No. 5,133,165. Such wall mounting systems were generally effective in providing a weather-tight seal and overcoming appearance problems, including eliminating the need for cutting out siding.
However, such devices have not been entirely satisfactory in all respects. For example, wall mounting brackets of the type disclosed by the MacLeod et al patent in U.S. Pat. No. 4,920,708 require first cutting out a portion of the front wall for installation of an electrical junction box. The junction boxes for installation in the MacLeod et al wall mounting brackets typically come equipped with holding flanges which must be opened and tightened manually by turning a threaded fastener after inserting into the front wall orifice of the mounting assembly to secure the box to the inside surface of the wall. Installation of such junction boxes during pre-wiring is often a tedious and unreliable process because the holding flanges often fail to readily open and securely engage with the inside portion of the wall mounting assembly. Furthermore, in the case of circular electrical junction boxes used in mounting heavier lighting fixtures there is a tendency for fixtures supported by cylindrically shaped junction boxes to turn or pivot on their axes because of the inability of the holding flanges on the junction boxes to reliably engage and lock against the front plastic wall of the mounting assembly to prevent such undesirable movement.
Carmichael discloses in U.S. Pat. No. 3,906,145 a mounting system for electrical fixtures wherein the electrical junction box is fabricated as an integral component with the wall mounting bracket. While the system of Carmichael eliminates the troublesome step of installing a separate electrical junction box this one-piece structure requires boring a large opening in the side wall of the building in order to install the unit. This can present special problems particularly when the side wall interior has other vertical supporting structures such as wall studs located where the electrical junction box portion of the assembly is to be positioned.
Accordingly, there is need for an improved wall mounting assembly for wiring and securing electrical devices, such as lighting fixtures, electrical outlets, receptacles for telephones and other communication equipment, etc., particularly on exterior walls of dwellings and other buildings whereby the installation process can be greatly facilitated without requiring significant structural alterations to mounting walls.